LOS ANGELES — Anthem Blue Cross has told some customers it will raise their health insurance premiums as much as 39 percent beginning March 1.

The increases, reported today by the Los Angeles Times, involve as many as 800,000 customers who buy individual coverage. People with group coverage aren’t affected.

In a statement, the Woodland Hills-based insurer declined to specify the size of the rate changes or how many people will be affected. The company — which is the largest for-profit health insurer in California — blames the increases on rising health care costs. It says its prices may be adjusted more frequently than its typical annual increases.